Figure 5.
A model of water flux in a leaf depending of the intensity of the transpiration stream. (A) In the well-watered condition without ABA, the water flux is large in the wt and even larger in the mutant plants; the Pos of the protoplasts from the mesophyll of the mutant plants is low. ABA treatment of wt and the aba1 mutant causes closure of the stomates, which leads to a decrease of the transpiration stream and an activation of the aquaporins in the plasma membranes of the mesophyll cells. (B) In hydroponics when the RH is low (45%), the water flux is large in the wt and even larger in the mutant plants; the Pos of the protoplasts from the mesophyll of the mutant plants is low (same as above). An increase of the RH to 85% leads to a decrease of the transpiration stream and strong increase of the water permeability of the mesophyll cells for all of the lines.